1) Field of the Invention
The invention relates to a wafer-type tumbler cylinder, the cylinder shaft of which facilitates the placement of the wafers and springs and, furthermore, one spring is positioned in a relatively wider rectangular notch, thereby serving as a shared spring for every two wafers. The amount of spring is reduced by half and it's able to prevent from prying or unlocking. Moreover, it's more convenient for lock makers to make and assemble various cylinders in different shapes or different length.
2) Description of the Prior Art
Conventional wafer-type tumblers, as shown in FIG. 14, are typically comprised of a sleeve 1a, a cylinder 2a, and a plurality of wafers 3a and their springs 4a. The sleeve 1a consists of a sleeve body 10 having a bore 11 extending through it lengthwise, a minimum of one lengthwise slot 12 disposed along the inside of the bore 11, and a bearing edge 13 at the leading end of the bore 11. As shown in FIG. 15, the cylinder 2a has a keyway 21 through the center and, furthermore, a flange 22 and a drive section 23 at the front and rear ends, with a shaft 20 movably installed in the bore 11 of the sleeve 1a; the shaft 20 has disposed one or more diametrically oriented, rectangular through-holes 24 and, furthermore, at the two sides of each rectangular through-hole 24 is a C-shaped recess 25 and a horizontally oriented U-shaped recess 26 (as shown in FIGS. 16 and 17), for the installation of one or more wafer 3a and spring 4a sets. The cylinder 2a, after the installation of the wafers 3a and their springs 4a, is first fitted into the bore 11 of the sleeve 1a and, furthermore, such that the one end of each wafer 3a is subjected to the elastic force of its spring 4a, and then postured against and inserted into the slot 12 inside the bore 11, thereby obstructing the clockwise and counter-clockwise rotation of the cylinder 2a situated in the bore 11; at the same time, the flange 22 at the front end of the cylinder 2a is seated on the bearing edge 13 at the leading end of the bore 11 in order to inset securely the bore 11; additionally, the drive section 23 at the rear end of the cylinder 2a is mounted with a lock tool or electric driver so as to check whether the tumbler is locked or electrified.
Because each wafer 3a of the conventional wafer-type tumbler, in addition to a window 31 in the middle thereof, has an opposing spring tab 32 and a locating tab 34; when the wafer 3a is inserted into each rectangular through-hole 24 on the shaft 20 of the cylinder 2a, it is first necessary to install a spring 4a into the C-shaped recess 25 at one side of the rectangular through-hole 24, following which the wafer 3a is then inserted into the rectangular through-hole 24; but during the installation, since the wafer body 30 of the wafer 3a has the spring tab 32, its insertion occurs without any resistance along the C-shaped recess 25; however, the locating tab 34, disposed in the other side of the wafer body 30, must similarly undergo insertion through the C-shaped recess 25 along the rectangular through-hole 24, and, as a result, friction occurs along the interior wall of the rectangular through-hole 24 at the lateral extent of the C-shaped recess 25, and only after this does the wafer body 30 reach into the horizontally oriented U-shaped recess 26, where it becomes nested onto the bottom of the horizontally oriented U-shaped recess 26 (as shown in FIGS. 16 and 17), and also only then is the cylinder 2a installed in the bore 11 of the sleeve 1a, which completes the assembly of one wafer-type tumbler mechanism. As such, during the insertion of each wafer 3a into the rectangular through-hole 24 on the shaft 20, the operation is difficult and adversely affects the production process. After each wafer 3a has been inserted into the rectangular through-hole 24, the locating tab 34 on the wafer body 30 is nested onto the bottom of the horizontally oriented U-shaped recesses 26; however, the height of the locating tab 34 is quite limited and, furthermore, the locating tab 34 is subjected to the outwardly exerted elastic force of the spring 4a, the wafer 3a is often ejected out of the rectangular through-hole 24. Such situation results in a troublesome and inconvenient assembly operation as the cylinder 2a is inserted into the bore 11 of the sleeve 1a, which likewise adversely affects the production process.
Moreover, based on the locking and unlocking structure of the conventional wafer-type tumbler, it depends entirely on the installation of the shaft 20 on the cylinder 2a with a plurality of wafers 3a; hence, as indicated in FIG. 15, the rectangular keyway 21 must be disposed through the center of the shaft 20 to facilitate insertion of the serrated blade 51 on the key 5a (as shown in FIG. 19), which causes each wafer 3a extending into the end of the slot 12 in the bore 11 to fully react within the outer diameter of the shaft 20, thereby achieving the objective of locking or unlocking. Since the cylinder 2a of the conventional wafer-type tumbler is typically made of aluminum-zinc alloy material in an integrated molding process, and the keyway 21 disposed through the center of the shaft 20 also penetrates the internal section of the shaft 20; as a result, it is not possible to mold a corrugated keyway having a narrow width. It's only possible to mold a keyway with a width of 1.5 mm or more, and as indicated in FIG. 14, the shape of the keyhole 211 only can be formed as reverse Z-shaped or other similar contour, which has a triangular projecting element 212 at the two lateral inner sides of the keyhole 211 respectively (one triangular projecting element is concealed by the flange 22, so it's not viewable); the keyway 21 along the internal section of the shaft 20 not only is formed as relatively wide rectangular shape, but also has disposed at most one lengthwise triangular projecting element 212 at one side of the keyway 21, as indicated in FIGS. 15 and 18. As a result, the prior art is easily broken by thieves and pried or unlocked by burglars.
Due to the shape of the keyway 21 and its keyhole 211 on the shaft 20 of the cylinder 2a in the conventional wafer-type tumbler, the design of which is formed as relatively wide rectangular and reverse Z-shaped contour, and furthermore, the two triangular projecting elements 212 are disposed in opposing position and at close distance along the two lateral inner sides of the keyhole 211; therefore, the serrated blade 51 of the key 5a must be fabricated of a thicker metal plate. Even though the whole key 5a may be formed by punching the metal plate, the serrated blade 51 (as indicated in FIGS. 19 and 20) must undergo milling or planing process to form as reverse Z-shaped section by means of a miller or planer, and it also has to undergo cutting or milling process to make a lengthwise V-shaped groove 511 at each of the lateral sides. Therefore, in terms of production, the process is extremely inconvenient and, furthermore, both time and labor consuming.
In view of the serrated blade 51 of the conventional wafer-type tumbler cylinder, there are such inconveniences and shortcomings during the process of production and assembly; such production cost is greater and not cost-effective and also the theftproof capability of the prior art still remained deficient, so the inventor of the invention herein conducted research which culminated in the improved wafer-type tumbler cylinder of the present invention.